1. Field of the Invention
This invention relates to vapor recovery and more particularly to an apparatus and a process of recovering flammable vapor emissions venting from a tank.
2. Description of the Related Art
In recent decades, public has become more aware of the hazards and ramifications of pollutants entering the atmosphere. These atmospheric pollutants range from simple, naturally occurring gases and/or vapors such as carbon dioxide to man made gases and/or vapors containing complex hydrocarbons. In an effort to control the amount of undesirable gases and/or vapors from entering the atmosphere, many countries have implemented laws to reduce and/or contain these undesirable gases and/or vapors from entering the atmosphere. Various solutions have been proposed by the prior art in an effort to eliminate or reduce the amount of undesirable gases and/or vapors from entering the atmosphere. These various solutions have been dependant on the types and quantity of the undesirable gases and/or vapors.
Some in the prior art have proposed the recovery and the recycling of the undesirable gases and/or vapors. Unfortunately, the devices proposed by the prior art for the recovery and the recycling of the undesirable gases and/or vapors are not economically feasible for the recovery of small quantities of undesirable gases and/or vapors. Accordingly, the prior art has merely “burned off” the small quantities of undesirable gases and/or vapors in an open flame. The open flame burning of the undesirable gases and/or vapors generates carbon dioxide and possibly other pollutants that enter the atmosphere during the burning process.
One specific example of the emission of small quantities of undesirable gases and/or vapors occurs during the refilling of a tank with a flammable liquid. As the tank is refilled with the flammable liquid, the residual vapors within the tank are displaced during the refilling process. Although the residual vapors could be recovered by a conventional recovery system, the cost of the conventional recovery system required to recover these vapors far exceeds the benefit of the recovery process. The following prior art references are examples of the attempts of the prior art to provide an economic system for recovering undesirable gases and/or vapors emitted into the atmosphere.
U.S. Pat. No. 4,380,146 to R. A. Yannone et al. discloses a gas turbine power plant including an industrial gas turbine that drives a rotating brushless exciter generator coupled to a power system through a breaker. One or more of the turbine-generator plants are operated by a hybrid digital computer control system during sequenced startup, synchronizing, load, and shutdown operations. The program system for the computer and external analog circuitry operate in a multiple gas turbine control loop arrangement. Logic macro instructions are employed in programming the computer for logic operations of the control system.
U.S. Pat. No. 4,745,868 to S. W. Seabury discloses a system for and method of producing a beneficiated fuel from a raw low ranked moisture ladened fuel. A combustion turbine is operated to provide a flow of exhaust gas out of an exhaust outlet at a temperature above ambient. The flow of exhaust gas is then directed across the raw low ranked moisture ladened fuel such that a portion of the moisture carried by the raw fuel is removed to produce the beneficiated fuel.
U.S. Pat. No. 4,957,049 to C. Strohmeyer, Jr. discloses an invention comprising an organic waste fuel combustion and tempering gas flow control system integrated with a gas turbine combined cycle steam generating plant. The gas turbine exhaust, wherein the oxygen content is partially consumed is used to dry and support combustion of an organic fuel high in moisture content after said fuel has been dewatered and pelletized. A portion of the gas turbine exhaust gas stream dries the pelletized waste fuel while a parallel portion of the gas turbine hot gas stream is used to support combustion and furnish oxygen in the ignition zone of the pelletized waste combustor. The drying stream also tempers secondary combustion gas temperature. The two gas streams are combined downstream of the combustion zone. The regenerated combined stream is then utilized in a steam generating section to generate steam. The gas turbine exhaust flow provides the mass flow and heat required for drying and combusting the pelletized waste fuel and the heat input from the pellet firing system regenerates the gas turbine exhaust gas stream. The pellet combustion process is maintained at temperature levels that avoid formation of deleterious products of combustion during the incineration process.
U.S. Pat. No. 5,666,825 to B. Darredeau et al. discloses a process and installation for the separation of air in a cryogenic distillation apparatus comprising a distillation column and in which the supplied air is separated to produce a fraction rich in oxygen and a fraction rich in nitrogen as products. The purities of these products are maintained substantially constant during variations of demand of either product or of the flow rate or of the pressure of the supplied air by introducing an excess of liquid rich in nitrogen into the distillation apparatus when the demand for the product or the flow rate of the supplied air increases, and by withdrawing an excess of liquid rich in nitrogen from the distillation apparatus, and storing this liquid, when the demand for the product or the flow rate of the supplied air decreases. The apparatus comprises a medium pressure column and a low pressure column and a reflux conduit which permits a reflux liquid to be withdrawn from the medium pressure column and to be injected into the low pressure column.
U.S. Pat. No. 6,066,898 to D. Jensen discloses a micro turbine power generating system including a combustor and a gas compressor that provides a flow of natural gas to a combustor. The flow of natural gas is regulated by varying the speed of the gas compressor for maintaining the gas compressor discharge pressure at a set point. The system further includes a turbine and an electrical generator that is driven by the turbine during a run mode of operation. A rectifier and a main inverter convert an output of the electrical generator into fixed frequency ac power during the run mode. A secondary inverter operates an electric motor of the gas compressor at the variables speeds during the run mode. During a startup mode, however, the main inverter operates the gas compressor motor, and the secondary inverter operates the electrical generator as a starter motor.
U.S. Pat. No. 6,141,628 to S. J. Worth et al. discloses a computer-implemented method and a computer-readable program for designing software applications for execution in a programmable logic controller including determining whether a physical input is analog or discrete, and responsive to the physical input being analog, inputting a set of analog parameters, and responsive to the physical input being discrete, inputting a set of discrete parameters, and storing the parameters in a user parameter data table. The method includes executing a programmable logic controller application responsive to a set of user-defined parameters, including reading an input, and determining whether the input is in fault, and, responsive to the input being in fault, performing an operation from a group of operations consisting of an alarm and a shutdown.
U.S. Pat. No. 6,170,251 to M. J. Skowronski et al. discloses a micro turbine power generating system including a primary compressor, an electrical generator and a turbine that can be rotated as a unit. Hot, expanding gases resulting from combustion are expanded through the turbine, and the resulting turbine power is used for powering the electrical generator. The micro turbine power generating system further includes an auxiliary compressor that is driven by the turbine power. During operation of the system, a small portion of air can be bled off the primary compressor and further compressed in the auxiliary compressor to provide an auxiliary supply of pressurized air. The heat of high-pressure compression is recovered to increase the overall efficiency of the machine.
U.S. Pat. No. 6,393,821 to E. Prabhu discloses a building structure enclosing a gaseous mixture of air and a combustible fuel. Air is obtained from the atmosphere, and the gaseous fuel is obtained from natural evolution and diffusion processes associated with rotting of materials, as from landfills, and gaseous digestion products from livestock, etc. A process control system is engaged for drawing off the gaseous mixture, at a selected air-fuel ratio, from the structure. The selected gaseous mixture is drawn from the building, through a compressor and then a pre-heater, into a catalytic combustor where the mixture is burned and directed into a turbine for producing work. This work is preferably converted into electricity by a generator driven by the turbine. A process controller senses process variables such as temperature, pressure, latent heat of fusion, etc. so as to assure that combustion cannot occur prematurely, but does occur most efficiently in the catalytic combustor. Process heat is exchanged for preheating the mixture to be burned.
It is an object of the present invention to provide an apparatus for recovering a flammable vapor emanating from a vent of a tank that is a significant advancement over the prior art.
Another object of this invention is to provide an improved apparatus for recovering a flammable vapor emanating from a vent of a tank that is capable of using flammable vapor normally vented to the atmosphere.
Another object of this invention is to provide an improved apparatus for recovering a flammable vapor emanating from a vent of a tank that is capable of recovering the energy of the flammable vapor normally vented to the atmosphere.
Another object of this invention is to provide an improved apparatus for recovering a flammable vapor emanating from a plurality of vents of tanks that is capable of accommodating varying quantities of the flammable vapor.
Another object of this invention is to provide an improved apparatus for recovering a flammable vapor emanating from a vent of a tank in safe and cost effective operation. The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by modifying the invention within the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment of the invention.